US4761591A - RPM regulation of an electromotor - Google Patents

RPM regulation of an electromotor Download PDF

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Publication number
US4761591A
US4761591A US07/027,492 US2749287A US4761591A US 4761591 A US4761591 A US 4761591A US 2749287 A US2749287 A US 2749287A US 4761591 A US4761591 A US 4761591A
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Prior art keywords
counter
comparator
input
motor
switching
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Expired - Fee Related
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US07/027,492
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English (en)
Inventor
Jurgen Hartwig
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Pfaff Haushaltsmaschinen GmbH
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Pfaff Haushaltsmaschinen GmbH
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Assigned to PFAFF HAUSHALTMASCHINEN GMBH, A GERMAN COMPANY reassignment PFAFF HAUSHALTMASCHINEN GMBH, A GERMAN COMPANY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: HARTWIG, JURGEN
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
    • H02P25/02—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the kind of motor
    • H02P25/10—Commutator motors, e.g. repulsion motors
    • H02P25/14—Universal motors
    • H02P25/145—Universal motors whereby the speed is regulated by measuring the motor speed and comparing it with a given physical value, speed feedback
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S388/00—Electricity: motor control systems
    • Y10S388/907—Specific control circuit element or device
    • Y10S388/91—Operational/differential amplifier
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S388/00—Electricity: motor control systems
    • Y10S388/907—Specific control circuit element or device
    • Y10S388/917—Thyristor or scr

Definitions

  • the present invention relates in general to motor controls, and in particular to a new and useful device for controlling the rotational speed of an electromotor.
  • a motor control containing a microcomputer is known from German DE-OS No. 28 33 981.
  • the control device contains a digital automatic control system which maintains a preset motor speed.
  • a counter is provided, which counts the number of oscillator pulses during a clock pulse of a tachogenerator connected to the motor shaft. This number is then taken as the basis of the actual number of revolutions for calculating a revolution number error, compared to the desired revolution number. This revolution number error is then used to correct the motor revolution number.
  • the present invention is drawn to a digital control for phase angle driven motors which responds to different preset numbers of revolutions with simultaneous precise regulation of the motor revolution number to a preselected number.
  • a parameter value is obtained which is simply determinable and digitally utilizable for a variable resistance use for determining the number of revolutions.
  • a separate oscillator can be dispensed with.
  • An object of the present invention is thus to provide a device for regulating the RPM of a motor having an RPM generator for generating pulses with rotation of the motor, intervals of the pulses being a measure of the RPM of the motor, comprising an oscillator for generating clock signals, a counter for receiving the clock signals, the counter counting the number of clock signals between successive pulses of the RPM generator, a register for accepting a count from the counter, control value means for generating a control value for controlling the RPM of the motor, a digital-to-analog convertor connected in series with the motor and connected to the control value means for applying the control value to the motor, the control value means comprising a RC-network containing a manually adjustable control resistor and a capacitor, a switch connected to the capacitor for short-circuiting the capacitor when the switch is activated, an oscillator-driven contact mechanism connected to the switch for activating the switch, and a circuit element connected to the contact mechanism for switching on the counter, the contact mechanism being connected to the counter for triggering
  • a further object of the invention is to provide a comparator as the oscillator-driven contact mechanism, the comparator having one impute which receives a stabilized direct-current, another imput which is connected to a voltage divider and an output which is connected to the base of a switching transistor which forms the switch.
  • a still further object of the invention is to utilize a second comparator as the circuit element, the second comparator being connected over a diode to the output of the first mentioned comparator, the output of the first mentioned comparator also being connected to the input of the counter for triggering the starting process of a triac which is connected to the motor for driving the motor.
  • Another object of the invention is to provide a device wherein the circuit element is connected over a differentiating circuit for switching the input of the counter.
  • a still further object of the invention is to provide a device for regulating the RPM of a motor which is simple in design, rugged in construction and economical to manufacture.
  • FIG. 1 is a schematic circuit of a first embodiment with a microcomputer for the speed control of a motor through phase angle control of a triac;
  • FIG. 2 is a graph that shows the course of the control current and level current at different points of the circuit
  • FIGS. 3 to 5 are flow diagrams with details of the program process steps of the programs stored in the program storage of the microcomputer
  • FIG. 6 is a schematic circuit of a second embodiment for RPM control of the motor
  • FIG. 7 is a graph that shows the course of the control and level currents at different points of the second circuit.
  • FIG. 8 is a flow diagram with details of the program process steps of the programs stored in the program storage of the microcomputer of the second circuit.
  • FIGS. 1 and 2 the invention embodied in FIGS. 1 and 2 comprises a device for regulating the RPM (revolutions per minute) of an electromotor.
  • FIG. 1 shows a motor 1 which is connected to a supply of alternating current and which is also connected in series to a triac 2.
  • the triac 2 is driven via a transformer 3a, with a starting circuit 3, which is connected to the output OUT .0. of a counter module 7 containing three counters (Z0, Z1, and Z2), which are connected via a data bus DB to a microcomputer 4.
  • the counter module 7 is an 8253-5 component, which has, in addition to internal function groups, a data bus buffer, a read/write logic, a check word register, and three count-down 16-bit counters.
  • the data bus buffer is a 3-state bidirectional 8-bit buffer and is the interface to the system data bus DB. It is essentially intended to carry out the functions and programming of different operating modes, loading the counter register and reading the counter content.
  • the read/write logic accepts data on the data bus DB of the microcomputer 4 and generates control signals for driving the individual module functions.
  • connection CE It is activated through the connection CE from an address bus AB of the microcomputer 4, which, in addition, has connections A0 and A1 for the selection of the three counters (Z0, Z1, Z2) of the counter module and the check word register.
  • the logic of module 7 is, moreover, connected to the microcomputer 4 at inputs RD for reading the counter contents and WR for loading the counters, and for writing a check word for the counter state.
  • the check word register contains information of the operational state of each counter (Z0, Z1, Z2), the selection of the number notation (binary or BCD), as well as for loading each counter register.
  • the three 16-bit counters (Z0, Z1, Z2) are identical countdown counters, which can work either in binary or in BCD (binary-coded decimal).
  • the computer 4 can load and read the counters (Z0, Z1, Z2).
  • the counting process is controlled by the particular GATE input (GATE .0., GATE 1 or GATE 2). Since all three counters (Z0, Z1, Z2) work in the same counter state (MODE 0), only this will be described here.
  • the counter output (OUT) voltage remains low while the counter modus is written on loading the particular counter (Z0, Z1, Z2) and during the counting process.
  • a timing disk 5 is firmly connected to the motor shaft 1a of the motor 1, which acts in conjunction with a pulse generator 6.
  • the timing disk 5 has a large number of line markings, from which the pulse generator 6 generates the pulse signals corresponding to the RPM. These are transmitted to the input TAKT of the microcomputer 4.
  • a rectifier 9 is connected to the alternating current.
  • the negative terminal 9b of rectifier 9 is connected to ground, and the positive terminal 9a of rectifier 9 is connected, via a resistor 10 and a Zener diode 11, to ground.
  • a capacitor 13 is connected to a connection 12 between the resistor 10 and the Zener diode 11. Capacitor 13 is grounded. A stabilized direct-current can thus be drawn over capacitor 13.
  • a voltage divider 14 is connected to connection 12 and consisting of resistors 15 and 16, with the resistor 16 connected to ground.
  • the connection point A between the two resistors 15 and 16 is connected to the inverted input of a comparator 17, while at the non-inverted input of the comparator 17 the connecting point B of two resistors 18 and 19, lies.
  • These resistors 18 and 19 form a voltage divider 20 and are connected between the connector 9a and ground.
  • the output of the comparator 17 is connected across a resistance 21 with the base of pnp switching transistor 22, the emitter of which is connected to the connection 12, and the collector of which is connected to a connection 23.
  • Connection 23 lies between two resistors 24 and 25 on one side, and a resistor 26 as well as a capacitor 27, on the other side.
  • the resistors 24 to 26 and the capacitor 27 form an RC network 28 located between the connection point 12 and ground.
  • the resistor 25 is fashioned as a potentiometer and, for practical reasons, is intended for manual operation.
  • connection point A between the resistors 15 and 16 of the voltage divider 14 is also connected to the inverted input of another comparator 29, the non-inverted input of which is connected to a connection point 30 between the resistor 26 and the capacitor 27.
  • the output of the comparator 29 is connected across a resistance 31 to the stabilized voltage of the connection point 12.
  • the output of the comparator 29 is connected via a diode 32 to the GATE .0. of the first counter Z0 of the counter module 7.
  • the output of comparator 29 is directly connected to the GATE 1 of the second counter Z1.
  • the connection 12 is connected to the GATE 2 of the third counter Z2.
  • the comparator 17 thus acts as an oscillator-driven contact mechanism which is connected to the transistor switch 22 for activating the switch.
  • the comparator 29 acts as a circuit element which is connected to the contact mechanism 17 for switching on the counter Z1.
  • the contact mechanism 17 is also connected so that it can trigger the counter to switch the counter off.
  • the output of the comparator 17 is connected to the GATE .0. of the counter Z0 and to an input NULLD of the microcomputer 4.
  • the circuit functions in the following way:
  • the supply voltage is rectified by the bridge rectifier 9 so that at point 9a the positive voltage of a pulsating direct-current results.
  • the bridge rectifier 9 operates therefore as an oscillator.
  • a direct-current largely stabilized by the Zener diode 11 and the capacitor 13, is obtained.
  • the timing disk 5 ccnnected to the motor shaft 1a rotates and generates pulses in the clock generator 6, the trailing edges of which trigger at the input TAKT of the microcomputer 4 in every instance a program INT 0 (FIG. 4).
  • the counter Z2 is read initially and subsequently cleared.
  • a constant "K" is added to the complemented value of the counter, Z2 and the result moved to register PERI.
  • the mean value between the momentary value in register PERI and the previous mean value contained in a register PERM is determined in order to balance strong RPM deviations.
  • the counter Z1 is read by the microcomputer 4, the value moved into a register R and the counter Z1, subsequently, cleared. It is then reset and switched to "gated", i.e. it only starts counting again when the voltage at the comparator 29 output is again high, that is, at the point, when charging of the capacitor 27 starts again. As soon as this charge exceeds the value determined by the reference voltage at the comparator 29, and its output receives again low voltage, the counter Z1 stops and is read by the next subprogram INT 1. On the basis of the counter indication, which corresponds to the elapsed time, the just set value of the resistor 25 is calculated. This is proportional to the elapsed time and thus, also to the counter indication.
  • a reference value for the RPM of 0 RPM, of 60 RPM or of 900 RPM is taken as basis. If the resistance 25 is between 1 K ⁇ and 19 K ⁇ , the reference RPM and the time to the starting pulse are calculated from it. Corresponding to the RPM value valid at a given time, a register SOLLW is loaded with the reciprocal of this number.
  • a subprogram ZUEND (FIG. 5) the starting angle for the control of the triac 2 is calculated from the values in the registers SOLLW and PERM and the value moved to register IMPULS. With the complement of the value from the register IMPULS, the counter Z0 is preset. It begins its down count when the output voltage of the comparator 17 and, thus, the voltage at its GATE input is high. With that, the start of the counter Z0 is independent of the different program execution times.
  • FIGS. 6 to 8 a second embodiment of the invention is shown.
  • two internal counters Z0 and Z1 of a microcomputer 4' are used.
  • the circuit of this embodiment therefore differs from the previously described in some details.
  • Identical modules are labeled with identical reference numbers. A special description was omitted in their cases. Similar modules, but connected differently, have been given a primed number.
  • the start circuit 3 is connected to an output ZUEND of the microcomputer 4'.
  • the output of the comparator 17 is connected across a resistance 21 to the base of an npn switching transistor 22', the emitter of which is connected to ground and the collector of which is connected to a connection 23'.
  • This lies between two resistors 24' and 25' on one side, and a resistor 26', as well as capacitor 27' on the other.
  • the resistors 24' to 26' and the capacitor 27' lie between the connection point 12 and ground. In this configuration, the resistors 24' to 26' and the capacitor 27' form an RC network 28'.
  • the resistor 25' is fashioned as a potentiometer and for practical purposes is intended for manual operation.
  • the connecting point A between the resistors 15 and 16 of the voltage divider 14 is also connected to the inverted input of an additional comparator 29', the non-inverted input of which is connected to a connecting point 30' between the resistor 26' and the capacitor 27'.
  • the output of the comparator 29' is connected across the resistance 31 to the stabilized voltage of the connecting point 12.
  • the output of the comparator 29' is connected via a capacitor 33 and a resistor 34 to the input of a NOR element 35.
  • the connection between the capacitor 33 and the resistor 34 is connected to ground via a resistor 36.
  • the output of the comparator 17 is connected across a resistance 37 with the connecting point 12 and directly with an input NULLD of the microcomputer 4' as well as with the second input of the NOR element 35.
  • the output of the NOR-element is connected to an input ANLS of the microcomputer 4'.
  • the timing disk 5 connected to the motor shaft 1a rotates and generates pulses in the clock generator 6, the trailing edges of which trigger, in each instance, at the input TAKT of the microcomputer 4', the program INT 0, the flow diagram of which is shown in FIG. 4.
  • the internal counter Z2 is read and its value used as RPM reference value.
  • a voltage a is applied given by the voltage divider 14, while at the inverted input B a rectified line voltage b is present reduced correspondingly by the voltage divider 20.
  • FIG. 7 the course of the corresponding voltage is shown.
  • rectangular pulses c are present which are transmitted every 10 msec over the connection NULLD to the computer 4'.
  • the leading edge of the rectangular pulse at the output C of the comparator 17 switches the transistor 22 to pass. Thereby, the capacitor 27 is discharged over the resistance 26'. As soon as the voltage at the inverted input B of the comparator 17 exceeds the voltage at the non-inverted input A, the output C voltage of the comparator 17 switches to low. The trailing edge of the rectangular pulse c blocks the switching transistor 22'. From this point on, the capacitor 27' is charged again over the resistors 24', 25', and 26'. Depending on the setting of the resistance 25', charging takes place with different increases. In FIG. 7, the course of the voltage d is shown at one setting of the resistance 25'. The voltage rises d' and d" at two different settings of the resistance 25' are shown in dashed lines.
  • the microcomputer 4' checks whether the voltage at its NULLD input is high. If this is the case, then the interrupt was caused by the zero passage of the line voltage, so that the following program sequence takes place:
  • a counter Z1, located in the microcomputer 4' is reset and switched to "gated", i.e. the counter Z1 starts to count only when the voltage in the connection ANLS is high again, thus, at the point, when the output voltage of the comparator 17 is low and charging of the capacitor 27' starts again.
  • the time until the start pulse is calculated by the microcomputer 4' in the subprogram ZUEND (FIG. 5) in the same way as in the first embodiment and the value stored in the storage location IMPULS provided for it.
  • the counter Z0 is loaded with the reciprocal value of this time value. This ends the line zero passage interrupt.
  • the counter Z1 is stopped, read and cleared. From the counter indication, which corresponds to the time used for charging the capacitor 27', the just set value of the resistance 25' is calculated. This value is proportional to the elapsed time and, thus, also to the counter indication.
  • the further program sequence for calculating the RPM reference values for starting the triac 2 corresponds to the measures as they were described already for the first embodiment.
  • the starting angle for the control of the triac 2 is calculated from the values in the registers SOLLW and PERM and with it an internal counter Z0 is preset. This begins to count up as soon as the voltage at the NULLD input of the microcomputer 4' is high. With this, the starting point of the counter Z0 is independent of the different program execution times.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Ac Motors In General (AREA)
  • Control Of Electric Motors In General (AREA)
  • Control Of Direct Current Motors (AREA)
US07/027,492 1986-03-21 1987-03-18 RPM regulation of an electromotor Expired - Fee Related US4761591A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3609566 1986-03-21
DE19863609566 DE3609566A1 (de) 1986-03-21 1986-03-21 Drehzahlsteuerung eines elektromotors

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US4761591A true US4761591A (en) 1988-08-02

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US (1) US4761591A (ja)
EP (1) EP0237717B1 (ja)
JP (1) JPS62272887A (ja)
DE (1) DE3609566A1 (ja)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2726921A1 (fr) * 1994-11-16 1996-05-15 Ela Medical Sa Procede d'ajustage d'un parametre electrique d'un dispositif electronique, notamment d'un stimulateur ou d'un defibrillateur cardiaque, et dispositif le mettant en oeuvre
US5621288A (en) * 1993-11-18 1997-04-15 Hitachi, Ltd. Motor speed regulating circuit with starter and storage medium drive using the same
US5726544A (en) * 1996-10-01 1998-03-10 Hyundai Motor Company Speed control apparatus and method for electric car
US6077238A (en) * 1996-02-29 2000-06-20 Homedics, Inc. Massaging apparatus with micro controller using pulse width modulated signals

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989005801A1 (en) * 1987-12-17 1989-06-29 E.I. Du Pont De Nemours And Company Antifungal carbinols

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3764876A (en) * 1971-10-01 1973-10-09 Storage Technology Corp Capstan control system for a tape drive
US3906319A (en) * 1973-10-04 1975-09-16 Lee J Milligan Universal motor speed control system
US3953776A (en) * 1973-12-14 1976-04-27 Waukesha Foundry Company, Inc. Digital motor speed control circuit
US4109184A (en) * 1976-03-19 1978-08-22 Ampex Corporation Method and apparatus for providing a stable, high gain servo system
US4130785A (en) * 1976-01-26 1978-12-19 Penet Pierre M M Control assembly for a cyclically operating powered unit
US4680516A (en) * 1986-05-30 1987-07-14 Guzik Technical Enterprises Motor speed control system
US4758625A (en) * 1985-02-06 1988-07-19 Albright & Wilson (Australia) Limited Acrylic crosslinked polymers

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3604996A (en) * 1968-09-26 1971-09-14 Warner Swasey Co Controlled power supply system
GB1510943A (en) * 1976-04-27 1978-05-17 Mullard Ltd Tachogenerator output signal processing circuits and motor speed control systems including such circuits
JPS5927013B2 (ja) * 1977-08-05 1984-07-03 富士通株式会社 磁気テ−プ送りモ−タの速度制御方式
JPS54147413A (en) * 1978-05-10 1979-11-17 Koyo Seiko Co Motor speed controller
US4513381A (en) * 1982-06-07 1985-04-23 The Singer Company Speed regulator for power tool
JPS5911272A (ja) * 1982-07-09 1984-01-20 Tokyo Electric Co Ltd レシ−ブプリンタ

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3764876A (en) * 1971-10-01 1973-10-09 Storage Technology Corp Capstan control system for a tape drive
US3906319A (en) * 1973-10-04 1975-09-16 Lee J Milligan Universal motor speed control system
US3953776A (en) * 1973-12-14 1976-04-27 Waukesha Foundry Company, Inc. Digital motor speed control circuit
US4130785A (en) * 1976-01-26 1978-12-19 Penet Pierre M M Control assembly for a cyclically operating powered unit
US4109184A (en) * 1976-03-19 1978-08-22 Ampex Corporation Method and apparatus for providing a stable, high gain servo system
US4758625A (en) * 1985-02-06 1988-07-19 Albright & Wilson (Australia) Limited Acrylic crosslinked polymers
US4680516A (en) * 1986-05-30 1987-07-14 Guzik Technical Enterprises Motor speed control system

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5621288A (en) * 1993-11-18 1997-04-15 Hitachi, Ltd. Motor speed regulating circuit with starter and storage medium drive using the same
FR2726921A1 (fr) * 1994-11-16 1996-05-15 Ela Medical Sa Procede d'ajustage d'un parametre electrique d'un dispositif electronique, notamment d'un stimulateur ou d'un defibrillateur cardiaque, et dispositif le mettant en oeuvre
EP0712641A1 (fr) * 1994-11-16 1996-05-22 ELA MEDICAL (Société anonyme) Procédé d'ajustage d'un paramètre électrique d'un appareil médical implantable et dispositif de mise en oeuvre
US5702426A (en) * 1994-11-16 1997-12-30 Ela Medical S.A. Automatic adjustment of electrical signal parameters
US6077238A (en) * 1996-02-29 2000-06-20 Homedics, Inc. Massaging apparatus with micro controller using pulse width modulated signals
US5726544A (en) * 1996-10-01 1998-03-10 Hyundai Motor Company Speed control apparatus and method for electric car

Also Published As

Publication number Publication date
DE3609566A1 (de) 1987-10-08
JPH0458275B2 (ja) 1992-09-17
DE3609566C2 (ja) 1988-02-18
EP0237717B1 (de) 1994-01-05
EP0237717A3 (en) 1988-08-31
JPS62272887A (ja) 1987-11-27
EP0237717A2 (de) 1987-09-23

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